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Objective:To study the impact on dose accuracy for the treatment planning by manually assigning accurate electron density for CT image-based tumor tissues and organs at risk.Methods:Twenty cases of retrospective postoperative cervical cancer radiotherapy plans were selected. The body electron density of the corresponding organs was derived from the ICRU 46 report and assigned in the treatment planning system (Monaco5.11, Sweden), including the bladder, rectum, intestine, kidney, spinal cord, femoral head, and ilium. The original plans were double-arc volumetric modulated arc therapy plan (360° VMAT), using Monte Carlo algorithm, the calculation grid was 0.3 cm × 0.3 cm × 0.3 cm, and the minimum subfield width was 0.6 cm. Keep the original plan fluence unchanged and recalculate the dose to generate a new plan. The two-dimensional dose distribution and dose-volume histogram (DVH) were used to compare the differences between the two plans. The difference was compared between the two group plans by using the dosimetry parameters and DVH two dimension curve.Results:For the planning of assigning bulk electron density (Plan RED), the deviation of the patient′s target dose parameters and the original plan (Plan ref) was <2%, and the average deviation of all target regions D2, D98, Dmean was < 0.7%, only 2 of the 180 data were between 2% and 3%. The average deviation of V20, V30, D1 cm 3, Dmean of the bladder, rectum, and small intestine, the original Plan ref was less than 0.6%, and 4 out of 240 data had values > 2%. Plan RED′s average hop count was 0.9% higher than Plan ref, and the total number of subfields remains unchanged. The planned dose generated by manually assigning the electron density in Plan RED was higher than that in Plan ref, but met the clinical requirements. The two-dimensional curves of the DVH diagram for targets and OARs almost completely overlapped, and there was no obvious difference in the dose distribution diagram of the same cross section. The statistical result of all parameters showed that the difference in planned dose parameters between the two groups was not statistically significant( P>0.05). Conclusions:The overall deviation of dose accuracy between Plan RED and Plan ref is <2%, which meets the clinical requirements and provides a reference for realizing MRI-only treatment planning.
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Objective:To investigate the diagnosis and clinical characteristics of five elderly patients with Chlamydia psittaci-caused severe pneumonia.Methods:Through retrospective analysis, diagnosis and treatment process and clinical characteristics of five elderly inpatients with severe pneumonia caused by Chlamydia psittaci were summarized in the Department of Critical Care Medicine, Quanzhou First Hospital East Street Branch Area, affiliated to Fujian Medical University between January to June 2021.Results:Five patients with severe pneumonia caused by Chlamydia psittaci were aged from 64 to 74 years, with various underlying diseases such as coronary heart disease, chronic heart failure, chronic obstructive pulmonary disease, etc.All patients had an established history of poultry exposure.These cases had high fever, cough, spitting, and dyspnea as the main clinical manifestations.Some of them also had systemic symptoms or weakness of the limbs as the prodromal symptoms.The disease progressed rapidly, with severe respiratory failure, acute kidney injury, and shock appearing soon, accompanied by different degrees of muscle injury, and damage to the heart, liver, blood coagulation, and immune systems at the same time.Laboratory examination showed that levels of inflammatory indicators were increased: at 3, 5, 7 d after admission, the level of C reactive protein was 214.6(153.9-256.3)mg/L, 199.2(115.8-333.8)mg/L, 151.0(11.19-173.7)mg/L, respectively; and interleukin 6 level was 1 241.0(912.1-6822.0)ng/L, 779.1(451.2-7122.0)ng/L, 631.2(7.0-4 321.0)ng/L, respectively.And monitoring results of nutritional index indicated a high metabolic state.The imaging examinations showed that consolidation and ground-glass shadows spreaded to both lungs, may accompany the miliary and nodular shadows, and may also involve pleural which caused pleural effusion.After the clinical use of metagenomic next-generation sequencing(mNGS), mNGS has been confirmed as an important method for the diagnosis of Chlamydia psittaci infection.The disease course and prognosis were related to the severity of the disease, advanced age, underlying diseases, and timely diagnosis and effective treatment.Conclusions:The progression of Chlamydia psittaci pneumonia to severe disease may be related to advanced age, more basic diseases such as chronic cardiopulmonary disease, smoking, and timely diagnosis and treatment.Generally, laboratory and imaging examinations have no diagnostic specificity, but mNGS is of great significance for early diagnosis, transition to target treatment and improvement of prognosis.
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Objective To compare the neck skin dose between fixed-field dynamic intensity-modulated radiation therapy (dlMRT),volumetric modulated arc therapy (VMAT),and helical tomotherapy (HT) in the treatment of early-stage nasopharyngeal carcinoma.Methods A total of 16 early-stage nasopharyngeal carcinoma patients undergoing radiotherapy were enrolled as subjects.The neck skin was delineated by contraction of the outer edge of neck by 3 mm.Dose planning was made by the traditional method (TP group)and a new method (NP group),in which the neck skin was considered as the organ at risk.Dmean and V5-V70 for the neck skin were recorded.The paired t-test was used to analyze the differences between two plans in each radiotherapy method.An analysis of variance was used to compare the same plan between the three radiotherapy methods.Results The HT group had significantly higher Dmean and V5-V70 for the neck skin than the dIMRT group and the VMAT group (P=0.00,0.00,0.00,0.00,0.00,0.00,0.00,0.02).Using dIMRT,the D and V10-V60 for the neck skin were reduced by 7％,8％,22％,25％,38％,59％,and 85％ in the NP group than in the TP group (P=0.00,0.00,0.00,0.00,0.00,0.00,0.00).Using VMAT,the D and V20-V40 for the neck skin were reduced by 4％,19％,29％,and 34％ in the NP group than in the TP group (P=0.02,0.01,0.02,0.01).Using HT,the V30-V60 for the neck skin were reduced by 20％,29％,50％,and 67％ in the NP group than in the TP group (P=0.00,0.00,0.00,0.00,0.03).Conclusions In the treatment of early-stage nasopharyngeal carcinoma,HT causes a higher radiation dose to the neck skin than dIMRT and VMAT,while dIMRT and VMAT have similar neck skin doses.The neck skin dose can be significantly reduced with the neck skin as the organ at risk.
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Objective To measure and analyze the neutron dose equivalent rate produced by an IORT accelerator with 9 and 12 MeV electron energyies,and compare them with those from a Siemens Primus linear accelerator with the same electron energy,in order to provide data reference for the risk of secondary cancer induced by radiotherapy.Methods Using the neutron detector LB6411,the neutron dose equivalent rates produced by the IORT accelerator of 9 and 12 MeV were measured on some key locations,such as the head of the accelerator,cylinder bottom,patient plane with electron energies 9 and 12 MeV.The similar measurements were also performed on the same locations on a Siemens conventional accelerator.The data were collected and analyzed and the result wer compared between the two accelerators.Results Neutron dose equivalent rates from the IORT accelerator with 9 MeV energy were (51.8±3.1),(45.5 ±1.5),(70.5 ±4.9) and (68.2±3.3) μ Sv/h near the head of the accelerator,cylinder bottom,patient plane,with 5.9％,5.4％,17.8％ and 21.5％ lower than at 12 MeV,respectively.The dose equivalent rates at the similar locations from the Siemens Primus accelerator were (277.3 ±1.2),(285.1 ±1.6),(185.1 ±1.8) and (182.8 ±2.4) μSv/h at 9 MeV,with 48.8％,47.6％,48.7％,52.2％ lower than those at 12 MeV,respectively.At the energy of 12MeV,the neutron equivalent dose rate from the IORT was lower by a factor of about 10 than for Siemens Primus accelerator.Conclusions The neutron dose equivalent rates generaged by both the IORT and the Siemens Primus are higher at 12 MeV than at 9 MeV,which would lead to an increased risk of secondary cancer to patients.The traditional medical accelerator produces much higher neutron dose equivalent rates than the intraoperative electron accelerator,for which the appropriate shielding should be takn.
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Objective To investigate the potential dosimetric advantages of half jaw volumetric modulated arc therapy ( H-VMAT) applied to the Oropharyngeal Cancer, comparing with full jaw VMAT (F-VMAT) and intensity modulated radiotherapy ( IMRT ). Methods Planning CT images of 10 oropharyngeal cancer patients were retrospectively chosen and transferred to Eclipse treatment planning system v. 11. 0 (Varian Medical Systems, Pala Alto, USA), based on which H-VMAT, W-VMAT, and IMRT plans were created. Two full arcs (360°) were adopted for VMAT planning, and the 7 beams were equally distributed for IMRT planning. The optimization constraints remained the same for the three kinds of plans. The dosimetric parameters such as D2 , D98 , D50 , HI, and CI were evaluated for PGTV, PCTV1, PCTV2, PGTVln, and PCTVln. In addition, the maximum dose (Dmax) and D1 cc(minimum dose received by 1cc) of the brainstem and spinal cord were analyzed respectively. The mean dose ( Dmean ) to the parotids, oral cave, larynx, and cervical normal tissues were also reviewed. The monitor units ( MU) for all treatment plans were recorded. Results Comparisons of the three planning techniques showed that H-VAMT improved the HI and CI of the targets (except PCTV2) significantly (HI: F =3. 959, 6. 764, 10. 581, 6. 770, 13. 040, P<0. 05;CI:F=6. 594, 4. 138, 0. 842, 4. 031, 5. 388, P<0. 05);reduced Dmax(F=4. 509, 20. 331, P<0. 05) and D1 cc for brainstem and spinal cord (F=27. 432, 26. 314, P<0. 05) significantly;reduced Dmean(F=4. 279, 29. 498, 19. 295, P<0. 05) to the normal tissues of the mouth, throat and neck significantly. The V50 of the mouth and throat were slightly lower in IMRT plans (F=8. 140, P<0. 05). IMRT was slightly better than W-VMAT in sparing oral cavity and larynx, but the dose distribution was the worst. The H-VMAT plans showed the best dose distribution in the cervical normal tissues, especially for the lower and posterior parts, where IMRT plans displayed high dose curves. Conclusions H-VMAT is dosimetrically superior than W-VMAT and IMRT for oropharyngeal cancer, which could be considered for clinical applications.
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Objective To compare dosimetric parameters between automatic three-dimensional conformal radiotherapy (a3DCRT),inverse three-dimensional conformal radiotherapy (i3DRT),inverse intensity-modulated radiotherapy (iIMRT).Methods Ten lung cancer patients with a single target and 10 intracranial tumor patients also with a single target,who were treated in our radiotherapy center from 2014 to 2015,were included in the study.Their image data were transferred to RayStation 4.5 via network,and then the treatment plans for a3DCRT,i3DCRT,and iIMRT were designed for the 20 patients.The dosimetric parameters for planning target volume (PTV) and organs at risk (OAR) were compared between the three plans using multiple dependent variables and two dependent variables.Results For lung cancer patients,iIMRT achieved better results in D98％,D50％,D2％,conformity index (CI),and homogeneity index (HI) than i3DCRT and a3DCRT (P=O.007,0.001,0.002,0.000,and 0.000),and the CI of a3DCRT was superior to that of i3DCRT (P=O.000);there were no significant differences in heart D33,spinal cord Dmax and D1 cm3,and both lungs between the three plans (P=O.702,0.237,0.163,0.739,0.908,0.832,0.886,0.722,0.429,0.840,and 0.702).For intracranial tumor patients,there were no significant differences in dosimetric parameters between the three plans,except that the CI of iIMRT and a3DCRT was superior to that of i3DCRT (P=O.648,0.783,0.256,0.931,0.002,and 0.034);there were no significant differences in whole brain irradiation dose between the three plans (P=0.446,0.755,0.772,0.0266,0.440,0.290,and 0.939).Conclusions For the single target in patients with lung cancer and intracranial tumors,a3DCRT can improve the CI of PTV compared with i3DCRT,and shows no significant dosimetric disadvantage for OARs compared with iIMRT.Considering the simplicity and low cost of 3DCRT,a3DCRT holds promise as a novel radiotherapy technique.
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Objective To compare the effective dose deposited in patients between helical tomotherapy (HT) and multi-ISO radiotherapy (M-ISO) in carniospinal irradiation (CSI).Methods Nine children with craniospinal irradiation were selected .For these patients , new plans were designed with HT and M-ISO centers planning method on the treatment planning system ( TPS) .The effective dose of the nine patients from 18 treatment plans were calculated ,and the difference of the effective dose between HT and M-ISO was compared using paired t-test.Results The plans designed in two groups were both satisfied all clinical requirements .For the planning target volume ( PTV ) , no statistically significant difference was found in D95% between two groups ( P>0.05 ) , while D98%, D2% and homogeneity index (HI) in HT group were superior to M-ISO group (t=2.762, 2.413, 4.563, P<0.05), D50%, Dmean and CI in M-ISO group were superior to HT group (t=5.259, 3.685, 7.815, P<0.05).HT and M-ISO had different advantages in the protection of the OARs .The effective dose of patients in M-ISO group was superior to HT group (t=5.921, P<0.05).Conclusions HT and M-ISO have different advantages in CSI.The low dose area has greater influence on the effective dose in HT group compared to M-ISO group. The low dose area should be concerned while designing the treatment planning for CSI .
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Objective The purpose of this study is to investigate the method to reduce the radiation dose to the neck skin in the Tomotherapy treatment plans for early-stage nasopharyngeal carcinoma.Methods The 17 patients with early-stage nasopharyngeal carcinoma that have been treated by the Tomotherapy were selected randomly for this skin sparing study.The neck skin sparing region was generated as an internal margin of 3 mm from the out body contour,excluding the intercrossed area with the targets.Candidate patients were planned using TP and NP method respectively:the TP group was planned with the traditional method.The new neck skin region was considered as an organ at risk (OAR) for planning dose constrain in NP group.The dosimetric metrics of targets and OARs,monitor units (MU) and delivery time were compared as the end points of these two groups.Results The two treatment plan groups satisfied the clinical requirement.There were no significant differences for D98,D95 and D2 of the targets (P ＞ 0.05).The Dmax of brainstem,D1cc of spinal cord,D of right parotid were higher in NP group than in theTPgroup (t =2.47,2.34,2.77,P＜0.05).The Dmax of left mandible joint was lower than TP group(t =2.30,P ＜ 0.05).The V30,V40,V50 and V60 of the skin were considerably lower than TP group (t =8.37,6.02,5.82,4.89,P ＜ 0.05).The mean MU and mean delivery time per fraction of NP group were 6.3％ and 8.1％ less than that of TP group respectively.Conclusions The neck skin region should be delineated as an OAR to be spared in the Tomotherapy treatment planning for early-stage nasopharyngeal carcinoma.This method can reduce the skin radiation dose effectively,alleviate the skin reaction,and improve the life quality of patients in radiotherapy.
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Objective To explore the application value of multi-ISO center planning method in intensity-modulated radiotherapy for carniospinal irradiation.Methods Ten patients treated with craniospinal irradiation with helical tomotherapy were selected.For these patients, new plans were designed with multi-ISO centers planning method on the treatment planning system (TPS) named Eclipse 11.0.Dose distribution to the tumor, OARs and normal tissue, the treatment time and the monitor units (MUs) of the two plans were compared.Results The plans designed in two groups satisfied all clinical requirements.For the tumor target (PTV) , the difference of D95％ between two groups was not statistical significant, while D9s ％ , D2 ％ and HI in HT group were superior to M-ISO group (t =2.822,2.333,4.743, P ＜0.05) , D50％ , D and CI in M-ISO group were superior to HT group (t =5.259,3.685,8.835 ,P ＜ 0.05).The dose of OARs such as cochlea, parotid, submandibular gland, thyroid gland and kidney in HT group was lower than M-ISO group (t =4.365,5.416,2.674,3.077,2.782,2.607,4.659,P ＜0.05) , and the dose of pancreas and small bowel was higher than M-ISO group (t =5.265,5.935, P ＜ 0.05).Differences were not significant for V5 of normal tissue between two groups;while V10, V20 and V36 of normal tissue in M-ISO group were lower than HT group (t =3.57,3.701,2.602, P ＜ 0.05).M-ISO group reduced 41.0％ of the treatment time by average and reduced 94.1％ MUs by average.Conclusions Intensity-modulated radiotherapy for carniospinal irradiation with multi-ISO centers planning method not only met the requirements of clinical dosimetry, but also shorten the treatment time, reduced the damage to the machine.Multi-ISO centers planning method might be promoted as a new design scheme.